基于随机森林算法的上海城市森林氧吧功能评估

Evaluation of Urban Forest Oxygen Function in Shanghai Based on Random Forest Algorithm

充分识别、科学评价城市森林氧吧资源,是发挥城市森林保健功效的前提,也是城市森林管理中亟待解决的问题。以上海城市公园中9个植物群落的长期监测数据为建模数据集,建立群落内空气负离子与气象条件、林分因子等指标的随机森林模型;在此基础上,根据2019年2月至2020年1月上海城市森林生态国家站和上海市气候中心的长期定位监测数据、上海市森林资源年度监测数据,评估上海市105处典型森林资源的负离子浓度,数据涵盖上海全域内公园绿地、生态片林、现有及拟开放休闲林地、现有及规划中的郊野公园,提出城市森林空气负(氧)离子评价等级标准。结果表明:105个城市森林群落中,全年空气负离子等级以Ⅱ级和Ⅲ级为主,Ⅳ级次之,Ⅰ级较少;负离子浓度主要呈现夏秋高、冬春低的季节变化规律;上海城市森林氧吧功能呈现空间分布不均的特征,应在人口密度高的中心城区打造更多的森林氧吧以满足居民的康养需求。结果可为上海市合理利用森林氧吧资源打造居民休闲游憩空间提供科学依据。

Identifying and evaluating this effect is one of the key problems to be solved in urban forest management.In this paper,based on the measured data of 9 long-term monitored plant communities in Shanghai’s urban Park,a random forest model was established linking negative air ions and other indicators such as meteorological conditions and plant factors.Then,based on the long-term monitoring data of Shanghai Urban Forest Ecosystem Research Station and Shanghai Climate Center from February 2019 to January 2020 and the annual monitoring data of Shanghai forest resources,this paper evaluated the concentration of the negative ions of 105 typical forest resources in Shanghai,which covers Shanghai’s urban parks,ecological forestry,country parks,and green leisure spaces.The results showed that in 105 urban forest communities,the annual air negative ion levels were mainly Ⅱ and Ⅲ.The concentration of negative ions is higher in summer and autumn than in winter and spring.By drawing an oxygen bar map,it is found that the spatial distribution of urban forest oxygen bars in Shanghai is uneven.More forest oxygen bars should be built in the central area of Shanghai with high population density to meet the residents’ demand for health care.This study can provide a scientific basis for the rational use of forest oxygen bar resources in Shanghai to create recreational space for residents and provide a valuable reference for other urban forest management.